Nicknamed "porpoise" (in French "marsouin") or "white porpoise", the beluga whale is usually found in arctic waters. Its Saint Lawrence population is the southern most and geographically the most isolated group from all the other populations of the Northern hemisphere(Pippard, 1985a; Sergeant and Hoek,1988).

The beluga whale of the Saint Lawrence has been listed, since 1983, as an endangered species by The Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Since nothing indicated, after revision in 1997, that the population was growing, the status was maintained by Campbell in 1998. The contamination and degradation of their habitat are the main threats to their recovery. This imminent danger lived by the beluga whale of the Saint-Lawrence was seen throughout the world and it is now one of its strongest ecological symbols regarding the protection of this magnificent river. The world's awareness toward the plight of the beluga launched the Saint Lawrence action plan to raise the quality of the river and the creation of the Marine park of the Saguenay-Saint Lawrence. Moreover, the beluga is the subject of a recovery plan which gives out the measures to take for its repopulation. (Recovery team, 1995).

The last inventory carried out by Gosselin and al. (2000) estimates the Saint Lawrence population at 952 + 134 belugas. The conclusion of this study is that this population has been stable since 1998. Seeing that beluga hunting was stopped at the start of the '80s, we should expect to see their numbers grow(Robert Michaud, personal communication). An estimate of 500 individuals was given in 1984 (Reeves Mitchell, 1984). The present numbers would then represent a fifth of the total population in the period before the nineteenth century's intensive hunting.

The Beluga is the only one of the whale species living in the Saint Lawrence year-round. Other whales migrate here only to feed. In the summer, the Beluga is found in the Saguenay and at the mouth of the fjord for some parts of the year. Although it can go up the fjord to Saint Fulgence in the summer, Michaud (1993) identified two intensive meeting areas for this sea mammal in the Saguenay: up the fjord between the Cap Boule area and the mouth of the Saguenay (near Tadoussac) and at the Baie Sainte Marguerite. Furthermore, according to pictures taken in the past fifteen years by the Sea mammal research and education group (GREMM, Groupe de Recherche et d'Éducation des Mammifères Marins) around one third of the Saint-Lawrence population is found in the Saguenay in the summertime. In the Saguenay, adult herds are seen either with their calves or by themselves (Michaud, 1993).

Many questions remain regarding the mating areas of the beluga in the Saguenay, mainly in the Baie Saint-Marguerite area. Feeding, resting and socializing activities are its main activities (Chadenet, 1997). The beluga feeds on marine inverterbrates living at the bottom of the fjord, such as the nereis worm and on many species of fish like the capelin, the tomcod, the plaice, etc. Since the beluga is situated at an important level of the food chain, it is thus sensitive to various chemical contaminants which could harm its health (Recovery team, 1995).

Since the beluga is found mainly in these two areas, it gives this sea mammal a capital ecological importance. Let us remind you that these two areas are located at the mouth of the Saguenay where maritime traffic can be a source of discomfort and annoyance for these sea mammals. It is of the utmost importance to ensure their protection in these areas especially when many calves are among the herds.